Michelle Obama back on book tour. How successful are first lady authors?

She noted that if you don’t have any suitable ground you can use containers. (She didn’t add that in the Washington area that’s a particularly good idea, because the natural soil resembles ground-up clay pots.)

Yes, it’s unusual for an author to still get personal appearances after a book’s been out 12 months. Mid-list authors with sensitive coming-of-age novels usually don’t get that treatment. But Random House probably figured that with gardening season just starting, a bit more publicity could push a more “American Grown” hardcover copies out the door. Profits go to the National Park Foundation, the official charity of the national parks.

Nowadays, first ladies just have to churn out books, don’t they? “American Grown” is the first by Obama, but we bet there are more to come. Every first lady since Lady Bird Johnson has eventually written a memoir of their White House years that received a large printing and full-press publicity, according to Craig Fehrman, an author who’s been researching a book about presidential books for several years.

This does not mean that books by first ladies are a purely modern phenomenon. The first presidential spouse to see her memoirs published while she was still alive was Helen Taft, whose book came out in 1914, according to Mr. Fehrman. Edith Wilson wrote a popular book. Eleanor Roosevelt was practically a publisher unto herself – she wrote dozens of tomes, from “Courage in a Dangerous World” to “Christmas, 1940” and “It’s Up to the Women."